Maximise Score

You are given $N$ segments where each segment is of the form $[L_i,R_i]$ $(1 \leq L_i \leq R_i \leq N)$. It is ensured that for any two segments $X$ and $Y$, one of the following conditions hold true: - $X \cap Y = X $, - $X \cap Y = Y $, or - $X \cap Y = \emptyset$ (empty set) Note that $\cap$ denotes the [intersection](https://en.wikipedia.org/wiki/Intersection_(set_theory)) of segments. In